1. She's a grieving cop's widow, prone to nymphomania, locked away in a shed behind her parents' home, profoundly damaged—not broken, but close. He's a bipolar basket case who nearly beat a man half to death for showering with his wife, the same wife with whom he obsessively wants to reconcile, even as he rocks back and forth in a mental institutions, whispering self-help mantras to himself while punching the wall. (This is a guy who has to psych himself down to go to a football game: "I won't get in a fight today, I won't, I won't.) It's tough to come up with more unlikely centers of a romantic comedy than Pat and Tiffany, played by Bradley Cooper and Jennifer Lawrence in Silver Linings Playbook, a film as unmoored and manic and big-hearted as its lead characters. I'm not sure I've seen a romance so imbued with this much danger since Punch-Drunk Love. This movie doesn't reach that film's cathartic highs, but it's based in the same world: This is about lost people finding each other.

2. The film begins with Pat being released from a mental hospital in Baltimore to his parents' home in Philadelphia. Dad (Robert De Niro) is an obsessive compulsive Eagles fan and gambling addict, Mom an enabling mother hen who wears a Kevin Kolb jersey most of the time just because she thinks it might help. Pat thinks he's doing better, but you'd probably argue otherwise. He's set off into fits of violence over nothing more than a particular song playing at the doctor's office. By accident, he gets set up with Tiffany, who immediately pegs him as someone crazier than she is, inspiring both sympathy and real intrigue. The rest of the film features them circling each other, warily, confused, yet undeniably drawn toward each other.

3. The film is gloriously messy, sometimes to its detriment. Writer-director David O. Russell specializes in the borderline insane, particularly men, attempting to make sense of their lives and the world around them, usually through the context of their equally eccentric extended family. Russell gives Silver Linings Playbook a jittery, jumpy, almost skittish quality that is both disorienting and riveting; like its central couple, it's a movie that has no idea where it's going, in a good way. It's the sort of film that bounces off the walls, and Russell's technique gets you inside these characters' heads; there are a couple times you think either Pat or the camera is gonna just jump out the window. But even though Russell may occasionally lose control—there's a oddly plot-heavy scene toward the end that makes no sense except to set up the ending—he never loses focus: This is a movie about Pat and Tiffany, and how much help they have to give each other.

4. The supporting cast ultimately is a bit of a distraction; Pat's parents' story is more conventional and therefore more familiar, and Chris Tucker pops up a couple times as an utterly superfluous fellow patient. But Silver Linings Playbook belongs to Cooper and Lawrence, both of whom are at their best. Cooper is an actor who didn't break through until his mid-30s, and you can see him relish such a strong part, the sort any actor would dream of. Pat is nervy, scared, and dangerous, but Cooper never overplays it. He has a deft way of making you never forget to cheer for him. (The movie's set in Cooper's native Philadelphia, and you sense his inherent comfort.) But the film belongs to Lawrence, who's basically a house afire. She's sexy, smart, and almost overwhelmingly sad, and in her grief she's basically ripping apart the rest of the world. When she realizes that Pat thinks she's crazier than he is, the scene is volcanic and a little terrifying. Lawrence is a huge star now because of The Hunger Games, but she is as natural an actress as anyone working right now. I'm pretty sure she's going to be this generation's next great, massive star, more Streep than Julia Roberts. This is the best she's been, and she's only going to get better.

5. At its core this is a romantic comedy, albeit one filtered through Russell's cracked sensibility, but it never follows any of the rhythms of a romantic comedy, and you probably won't recognize it as one until the end. It's a neat bit of misdirection: You find yourself so worried that Pat and Tiffany are going to lose their shit entirely that you don't notice just how intricately they're wrapped up in each other's lives. Whether the movie—which is often busy jumping up and galloping after every shiny object, like an overeager, inbred puppy—earns its big last half-hour is sort of beside the point. Pat and Tiffany definitely have. It's impossible not to pull for them, even when you'd run screaming away in real life. Silver Linings Playbook is a wild mess, but what a mess it is.

Grade: B+.

Grierson & Leitch is a regular column about the movies. Follow us on Twitter, @griersonleitch.